As an aside, this freedom of choice for smart girls certainly accounts for some of the variance in the percentage of Nobel Prizes won by women in the pre- and post-women’s liberation periods. Once women were allowed to enter the professions, they won fewer “hard” Nobel Prizes, indicating that some of the female scientists and mathematicians of the past would likely have preferred to practice medicine or law, but had no other choice than to conduct research. McKellar, her sister, and most of the women from the testimonials are cases-in-point: they are all great at math, yet only one has chosen a career as a research scientist.
The author herself majored in math at a prestigious university, graduated summa cum laude, and shares credit for a math/physics proof — how much more positive encouragement could she need if she truly wanted to be a research mathematician? She just prefers what more women than men prefer to do with their lives: to work more with people than objects, and to help and nurture more than to figure out how things work.

A lot more men than women choose to do seemingly irrational things such as become petty criminals, fly homebuilt helicopters, play video games, and keep tropical fish as pets (98 percent of the attendees at the American Cichlid Association convention that I last attended were male). Should we be surprised that it is mostly men who spend 10 years banging their heads against an equation-filled blackboard in hopes of landing a $35,000/year post-doc job?

and

1. young men strive to achieve high status among their peer group
2. men tend to lack perspective and are unable to step back and ask the question “is this peer group worth impressing?”